Identify the colour change observed when $NaCl$ solution is titrated against $AgNO_3$ solution using fluorescein as an indicator.

$110 \, mL$ of $0.1 \, N \, HCl$ is titrated with $30 \, mL$ of $0.2 \, N \, NaOH$. The remaining titration is completed by adding $0.25 \, N \, KOH$ solution. What volume of $KOH$ in $mL$ is required?

In a conductometric titration,a small volume of titrant of higher concentration is added stepwise to a larger volume of titrate of much lower concentration,and the conductance is measured after each addition.
The limiting ionic conductivity ( $\Lambda ^0$ ) values (in $mS \ m ^2 \ mol ^{-1}$ ) for different ions in aqueous solutions are given below:

Ions	$Ag ^{+}$	$K ^{+}$	$Na ^{+}$	$H ^{+}$	$NO _3^{-}$	$Cl ^{-}$	$SO _4^{2-}$	$OH ^{-}$	$CH _3COO ^{-}$
$\Lambda _0$	$6.2$	$7.4$	$5.0$	$35.0$	$7.2$	$7.6$	$16.0$	$19.9$	$4.1$

For different combinations of titrates and titrants given in List-$I$,the graphs of 'conductance' versus 'volume of titrant' are given in List-$II$.

List-$I$	List-$II$
$(P)$ Titrate: $KCl$,Titrant: $AgNO _3$	$(1)$ Graph showing initial decrease then increase
$(Q)$ Titrate: $AgNO _3$,Titrant: $KCl$	$(2)$ Graph showing sharp decrease then sharp increase
$(R)$ Titrate: $NaOH$,Titrant: $HCl$	$(3)$ Graph showing slight decrease then increase
$(S)$ Titrate: $NaOH$,Titrant: $CH _3COOH$	$(4)$ Graph showing continuous increase
	$(5)$ Graph showing decrease then constant

Match each entry in List-$I$ with the appropriate entry in List-$II$ and choose the correct option.

$8 \ mL$ of $\frac{N}{10} \ HCl$ are required to neutralize $20 \ mL$ of $Na_2CO_3$ solution in water. The normality of the $Na_2CO_3$ solution is: (in $N$)

In the volumetric analysis of $HCl$,if we use phenolphthalein as an indicator,which base is unsuitable for titration?

Why are strong acids generally used as standard solutions in acid-base titrations?